Most modern buildings use some sort of an HVAC system to control the environment conditions inside of the building. Such HVAC systems can be configured to control a number of different environmental conditions including, for example, temperature, humidity, air quality and/or other environmental conditions, as desired. In many HVAC systems, air from the building's inside space is drawn into return ducts and provided back to the HVAC system, where the return air is conditioned and provided back to the inside space. To meet desired ventilation requirements, some HVAC systems include an economizer and/or demand control ventilation system (DCV). Such systems often include an exhaust port for exhausting at least some of the return air to the outside environment, and/or an intake port for bringing fresh air into the HVAC system. In some instances, a damper system including one or more dampers is provided to control how much return air is exhausted and/or how much outside air is brought into the building. In many instances, the air supplied by the HVAC system to the inside space can be a mixture of fresh outside air and return air, depending on the conditions. To maintain the energy efficiency of the HVAC system, it may be useful to ensure that the dampers are functioning properly.